26 BULLETIN OF THE 



-c Craniacece Menke, Syn., p. 56, 1828,* olim. 



-c Craniacea Menke, Syn., Ed. II, p. 96, 1830. — ANTOTT Verz., p. xii, 



1839. — Agassiz, Nomencl. Fasc. IX, p. 31, 1846. — Mcerch, Cat. 



Yoldi, p. 64, 1852. 

 ^zCraniidce Forbes, Mai. Mon., p. 38, 1838* — King, Ann. Nat. Hist., 



XVIII, p. 28, 1846. Perm. Fos., p. 78, 1850. 

 -=: Craniadai Forbes and Hanley, Brit. Moll., II, p. 364, 1853. 

 ^cLes Orbicules Cuvier, Lecons d'Anat. Comp. An. VII, I, t. 5, 1798* 



(fide Gray). Regne An., II, p. 504, 1817 ; Tabl. El. Hist. Nat., p. 



435, 1799. 

 ^cAthjridw McCoy, Carb. foss. Irel., p. 104, 1844. 

 -=cOrbieuke Herrmannsen, Index Gen. Mai., II, p. 156, 1847 (as of 



Desha yes). 

 -c Les Oslrace'es Lam., Phil. Zool., 1809* (Ed. 1830, p. 31 7.) 

 ~^Plaeunea Rafinesque, Anal. Nat., p. 148, 1815. 

 ■^ Fixivalvia Latreille, Fam. Nat. Regn. An., p. 205, 1825. (Ed. Berth, 



p. 196.) 

 -= Palliobranches a coquilles non symmetriques Blainville, Man. Mai., p. 



515, 1825. 

 -=: Terebratulidea G. B. Sowerby, Trans. Lin. Soc., XIII, p. 469, 1822. 



Shell calcareous ; hingeless ; without perforation for a pedicel ; attached 

 by the umbones of or the entire lower valve, or rarely free. Upper valve 

 suborbicular, with a subcentral apex. Lower valve subcircular or pyri- 

 form. Four principal muscular impressions in each valve. Shell struc- 

 ture punctate. Animal with free spiral arms, the direction of the apex of 

 the spires toward the concavity of the upper or ha?mal valve. Mantle 

 extending to the edge of the valves, closely adhering, without seta? upon 

 its external edge. Animal holding the same relation to the attached 

 valve which obtains in the Terebratulidcc, but actually reversed in relation 

 to surrounding objects, on account of the attachment being by the surface, 

 instead of by the recurved apex, of the neural valve. 



Synopsis of the Family. 



Genus Crania Retz: Shell attached ; upper valve with the muscular impres- 

 sions usually excavated, but occasionally convex, without apophyses of 

 any kind, inner surface vaulted, without septa; impressions of the pallial 

 sinuses flabclliform, separated in front. Margin of the valves tubercu- 

 lose or papillose. Type Crania craniolaris, Lin. sp. Syst. Nat., Ed. XII, 

 p. 1150, 1767. 



?1 Subgenus Pseudocrania McCoy. Shell free, with the impressions of the 

 pallial sinuses fimbriated and confluent in front. Margins smooth. Ante- 

 rior muscular impressions larger than the posterior ones. Type Crania 



